<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>04_Bootrstap-网格系统基本使用</title>
  <link rel="stylesheet" href="./libs/bootstrap-4.6.1/css/bootstrap.css">
  <style>
    .container {
      background-color: pink;
    }
    .item {
      height: 40px;
      border: 1px solid red;
    }
  </style>
</head>
<body>

  <h3>3等份</h3>
  <div class="container">
    <div class="row">
      <div class="col item">1</div>
      <div class="col item">2</div>
      <div class="col item">3</div>
    </div>
  </div>

  <h3>网格系统(启用了12列,超出12列就会换行)</h3>
  <div class="container">
    <!-- 
      display:flex
      flex-wrap: wrap
     -->
      <div class="row">
        <!-- 
          flex item:  
            flex-basis: xx%
            max-width: xx%
            flex-grow: 0,
            flex-shrink: 0
         -->
        <div class="col-4 item">1</div>
        <div class="col-4 item">2</div>
        <div class="col-4 item">3</div>
        <div class="col-6 item">4</div>
      </div>
   </div>
  
</body>
</html>